Improvement in gun-carriages



2 Sheets Sh'eet; I.

G. BIRKBECK, Jr. Gun Carriage.

No. 44,506. Patented Oct. 4, 18 64.

inventor: MM 0 NPETERS, PHOTCLUTHOGRAFIH ER, WASHINGTON. Dv E:v

' 2 sl lets sheet 2. G. BIRKBECK, Jr.

Gun Carriage. No. 44.506. PabentedOct. 4, 186 1.

N. PETERS. PHDTO4JTMOGRAPNER, WASHINGTON, D C.

' Improvements in Gun-Carriages; and I do explosion have a tendency to break or bend GEORGE BIBKBEOK, JR,

PATENT- OFFICE.

OF NEW YORK, N. Y.

IMPROVEMENT IN GUN-CARRIAGES.

Specification forming part of Letters Patent No. 441,506. dated October ,1864.

To all whom it may concern.-

Be it known that I, GEORGE BIRKBEOK, J r., of the city, county, and State of New York, have invented certain new and useful hereby declare the following to be a full, clear, and exact description of the same, reference being had tothe annexed drawings, making part of this specification, in which- Figurel is a top view, Fig. 2 a side eleva tion, and Fig. 3 is abreech elevation, of a gun and carriage with my improvement applied thereto.

My invention relates more especially to the improvement of what is known as the Erics son gun-carriage, as adapted to the monitor and other class of vessels, with the Ericsson revolving turret; but it may be advantageously applied to any gun-carriage intended for large guns as hitherto constructed, where tail-screws of great length have hitherto been necessary to elevate and depress the gun.

The drawings show one of Dahlgrens fifteen-inch guns set in the Ericsson gun-carriage above referred tarwith my improvement attached. The base-plate of this carriage is a horizontal plane, A, which projects beyond the rear ends of the side plates or trunnionbearings 13, as shown by O, to form a bearing for the tail-screw D.-

It has hitherto been the practice in the use Of the guns of vessels, where tail-screws were required, to employ tail-screws long enough to reach from the breech-tail of the gun to the base-piece A of the carriage. Now, when the axis of the gun lies on a horizontal plane the tail-screw stands upon a vertical plane, or

very nearly so, and is in that position capable of supporting the preponderating (if any) weight of the breech, and also to resist with out injury the force upon it incident to the discharge of the gun; but when the muzzle of the gun is elevated for the purposes of long range or elevation the tail-screw will set at an angle with the plane upon which it bears or is supported, so that the prepondering weight of the breech of the gun and the force of the the tail-screw, and. they frequently do break or bend where the screw is of necessity of considerable length. To overcome this defect in the mechanical relation of the guns and carriages is the Object of my invention; and it consists in the application of an elevated bearing-piece attached to the manor breech end of the carriage for the foot of the tail-screw to rest upon. This bearing-piece is represented in the drawings by E. It is a circular piece of metal, made to span the breech of the gun, and is securely bolted to the baseplate, end, and side frames of the gun-carriage in the manner shown, andon its upper side or edge, in the center under the tailscrew of the gun, is formed a head or base, F, reaching up toward the breech-tail of the gun for the tail-screw torest upon. By the use of this head or base for the tail-screw to rest upon the tail-screw may be very much shortened in length, and the sine of the angle formed by the tail-screw and base-plate of the gun-carriage correspondingly lessened, which will lessen the liability of the tail-screw to bend or break whenever the gun is fired.

The drawings show the form of bearingpiece I have applied to two of the gun-carriages now in use. This formof bearingpiece may, however, be modified to suit the circumstances that govern it; but it should-be so made as to be out of the way of the breech of the gun, and so as to substantially strengthen the rearend or base-plate A of the guncarriage as much as is necessary.

What I claim as new and as an improvement on the Ericsson gun-carriage, and-desire to secure by Letters Patent, is-

The application of a bracket, E, to the rear end of the carriage, so made and applied as to form an elevated bearing for the tail-screw,-

and at the same time strengthen the rear end of the carriage by transferring a part of the force on the tail-screw to the side frames of the carriage.

GEORGE BIRKBEOK, JR.

Witnesses:

A. K. LITTLEFIELD, GEORGE DANDT. 

